19. AMEDEO AVOGADRO

(August 9, 1776 – July 9, 1856) Like some great scientists before him, this physics professor studied religion and law before opting for science. And just like his compatriot, Alessandro Volta, who cashed-in on what eluded Luigi Galvani, Avogadro explored facts which Joseph Louis Gay-Lussac overlooked, alongside those that stumped John Dalton. This led him into researches which resulted in his contributions to Molecular Theory. His famous law (sometimes called hypothesis) propelled Physics and Chemistry to loftier heights. This is noteworthy because Avogadro lived in an era when the terms “atom” and “molecule” were used interchangeably. He tried to tidy-up things: starting from where Gay-Lussac and Dalton stopped. In the process, he ushered-in a new era of Particle Physics. His researches were so ahead of their time that none of his contemporaries showed interest in them. It was after three years, when André-Marie Ampère rediscovered few of them, that scientists gave them second thoughts. A series of Organic Chemistry experiments which Auguste Laurent and Charles-Frédéric Gerhardt later conducted, supported Avogadro’s claim that equal volumes of all gases contain equal number of molecules (at constant temperature and pressure). However, Avogadro was already dead in 1860 when Stanislao Cannizzaro detailed the greatness of his works. They not only determined molecular masses, but atomic masses as well. Several more years would pass before the depths of his works were fully appreciated. Still, his contributions did consolidate his place as one of the founders of Molecular Theory. He is the eponym of the mineral Avogadrite and the lunar crater Avogadro.

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